pub struct View<Buffer, P: Pixel>{ /* private fields */ }
Expand description
A flat buffer that can be used as an image view.
This is a nearly trivial wrapper around a buffer but at least sanitizes by checking the buffer length first and constraining the pixel type.
Note that this does not eliminate panics as the AsRef<[T]>
implementation of Buffer
may be
unreliable, i.e. return different buffers at different times. This of course is a non-issue for
all common collections where the bounds check once must be enough.
§Inner invariants
- For all indices inside bounds, the corresponding index is valid in the buffer
P::channel_count()
agrees withself.inner.layout.channels
Implementations§
source§impl<Buffer, P: Pixel> View<Buffer, P>
impl<Buffer, P: Pixel> View<Buffer, P>
sourcepub fn into_inner(self) -> FlatSamples<Buffer>
pub fn into_inner(self) -> FlatSamples<Buffer>
Take out the sample buffer.
Gives up the normalization invariants on the buffer format.
sourcepub fn flat(&self) -> &FlatSamples<Buffer>
pub fn flat(&self) -> &FlatSamples<Buffer>
Get a reference on the inner sample descriptor.
There is no mutable counterpart as modifying the buffer format, including strides and
lengths, could invalidate the accessibility invariants of the View
. It is not specified
if the inner buffer is the same as the buffer of the image from which this view was
created. It might have been truncated as an optimization.
sourcepub fn samples(&self) -> &Buffer
pub fn samples(&self) -> &Buffer
Get a reference on the inner buffer.
There is no mutable counter part since it is not intended to allow you to reassign the buffer or otherwise change its size or properties.
sourcepub fn get_sample(&self, channel: u8, x: u32, y: u32) -> Option<&P::Subpixel>
pub fn get_sample(&self, channel: u8, x: u32, y: u32) -> Option<&P::Subpixel>
Get a reference to a selected subpixel if it is in-bounds.
This method will return None
when the sample is out-of-bounds. All errors that could
occur due to overflow have been eliminated while construction the View
.
sourcepub fn get_mut_sample(
&mut self,
channel: u8,
x: u32,
y: u32
) -> Option<&mut P::Subpixel>
pub fn get_mut_sample( &mut self, channel: u8, x: u32, y: u32 ) -> Option<&mut P::Subpixel>
Get a mutable reference to a selected subpixel if it is in-bounds.
This is relevant only when constructed with FlatSamples::as_view_with_mut_samples
. This
method will return None
when the sample is out-of-bounds. All errors that could occur due
to overflow have been eliminated while construction the View
.
WARNING: Note that of course samples may alias, so that the mutable reference returned here can in fact modify more than the coordinate in the argument.
sourcepub fn min_length(&self) -> usize
pub fn min_length(&self) -> usize
Get the minimum length of a buffer such that all in-bounds samples have valid indices.
See FlatSamples::min_length
. This method will always succeed.
sourcepub fn image_slice(&self) -> &[P::Subpixel]
pub fn image_slice(&self) -> &[P::Subpixel]
Return the portion of the buffer that holds sample values.
While this can not fail–the validity of all coordinates has been validated during the
conversion from FlatSamples
–the resulting slice may still contain holes.
sourcepub fn image_mut_slice(&mut self) -> &mut [P::Subpixel]
pub fn image_mut_slice(&mut self) -> &mut [P::Subpixel]
Return the mutable portion of the buffer that holds sample values.
This is relevant only when constructed with FlatSamples::as_view_with_mut_samples
. While
this can not fail–the validity of all coordinates has been validated during the conversion
from FlatSamples
–the resulting slice may still contain holes.
sourcepub fn shrink_to(&mut self, width: u32, height: u32)
pub fn shrink_to(&mut self, width: u32, height: u32)
Shrink the inner image.
The new dimensions will be the minimum of the previous dimensions. Since the set of
in-bounds pixels afterwards is a subset of the current ones, this is allowed on a View
.
Note that you can not change the number of channels as an intrinsic property of P
.
sourcepub fn try_upgrade(self) -> Result<ViewMut<Buffer, P>, (Error, Self)>
pub fn try_upgrade(self) -> Result<ViewMut<Buffer, P>, (Error, Self)>
Try to convert this into an image with mutable pixels.
The resulting image implements GenericImage
in addition to GenericImageView
. While this
has mutable samples, it does not enforce that pixel can not alias and that samples are
packed enough for a mutable pixel reference. This is slightly cheaper than the chain
self.into_inner().as_view_mut()
and keeps the View
alive on failure.
let mut buffer = RgbImage::new(480, 640).into_flat_samples();
let view = buffer.as_view_with_mut_samples::<Rgb<u8>>().unwrap();
// Inspect some pixels, …
// Doesn't fail because it was originally an `RgbImage`.
let view_mut = view.try_upgrade().unwrap();
Trait Implementations§
source§impl<Buffer, P: Pixel> GenericImageView for View<Buffer, P>
impl<Buffer, P: Pixel> GenericImageView for View<Buffer, P>
source§fn dimensions(&self) -> (u32, u32)
fn dimensions(&self) -> (u32, u32)
source§fn get_pixel(&self, x: u32, y: u32) -> Self::Pixel
fn get_pixel(&self, x: u32, y: u32) -> Self::Pixel
source§fn in_bounds(&self, x: u32, y: u32) -> bool
fn in_bounds(&self, x: u32, y: u32) -> bool
source§unsafe fn unsafe_get_pixel(&self, x: u32, y: u32) -> Self::Pixel
unsafe fn unsafe_get_pixel(&self, x: u32, y: u32) -> Self::Pixel
source§fn pixels(&self) -> Pixels<'_, Self> ⓘwhere
Self: Sized,
fn pixels(&self) -> Pixels<'_, Self> ⓘwhere
Self: Sized,
source§fn view(&self, x: u32, y: u32, width: u32, height: u32) -> SubImage<&Self>where
Self: Sized,
fn view(&self, x: u32, y: u32, width: u32, height: u32) -> SubImage<&Self>where
Self: Sized,
GenericImage::sub_image
if you need a mutable view instead.
The coordinates set the position of the top left corner of the view.